Devices, system and methods for minimally invasive glaucoma surgery

ABSTRACT

Devices and methods useable for forming opening in trabecular meshwork of mammalian eyes.

RELATED APPLICATIONS

This patent application claims priority to copending U.S. Provisional Patent Application No. 62/460,061 filed Feb. 16, 2017 and copending U.S. Provisional Patent Application No. 62/584,613 filed Nov. 10, 2017, the entire disclosure of each such application being expressly incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to the fields of medicine and engineering and more particularly to surgical devices and methods for performing surgery.

BACKGROUND

Pursuant to 37 CFR 1.71(e), this patent document contains material which is subject to copyright protection and the owner of this patent document reserves all copyright rights whatsoever.

One surgical procedure used to treat certain types of glaucoma is a goniectomy. In a surgical goniectomy, a tissue cutting or ablating device is inserted into the anterior chamber of the eye and used to remove a full thickness strip of the tissue from the trabecular meshwork overlying Schlemm's canal. In many cases, a strip of about 2 mm to about 10 mm in length and about 50 μm to about 500 μm in width is removed. This creates a permanent opening in the trabecular meshwork through which aqueous humor may drain. The goniectomy procedure and certain prior art instruments useable to perform such procedure are described in U.S. patent application Ser. No. 10/052,473 published as No. 2002/0111608A1 (Baerveldt), the entirety of which is expressly incorporated herein by reference.

For opening of the trabecular meshwork (TM) to lower intraocular pressure (IOP) for treatment of the eye disease glaucoma, the procedure needs to remove a strip of the TM overlying Schlemm's canal. Furthermore, the distal or back wall of Schlemm's canal, with its ostia for drainage of aqueous humor from the eye via the collector channels, must be protected so that their efficacy is maintained.

If the device only makes a single cut (like a classical goniotomy knife used for surgical management of pediatric glaucoma), all of the TM tissue remains behind. For adults, the outcomes for such a procedure may be prone to having the access of fluid drainage via the collector channels in Schlemm's canal become blocked over time as this remnant tissue clogs such access for fluid outflow via the collector channels. Furthermore, if the back wall of Schlemm's canal and its outflow ostia are injured during the procedure, their drainage efficacy will most likely be compromised. A device that protects the back wall of Schlemm's canal while removing a strip of TM also greatly enhances the safety of such a procedure (i.e. providing a means for preventing cutting too deep and thus cutting into the back wall of Schlemm's canal.

In addition, such a device must be properly sized for ab-interno access through a small incision into the anterior chamber of the eye (typically a small corneal incision). Furthermore, the working end or distal tip of such a device must also be properly sized relative to the anatomy of Schlemm's canal, and it must be properly oriented with respect to the shaft that transverses between the incision point and the treatment zone of Schlemm's Canal in order to be functional.

There remains a need in the art for the development of new goniotomy devices and methods whereby a strip of TM tissue is removed to expose the ostia of collector channels in the lateral or outer wall of Schlemm's canal, thereby allowing aqueous humor to freely drain from the anterior chamber of the eye through those collector channels which in turn results in a lowering of intraocular pressure in the treated eye.

SUMMARY

In accordance with the present invention, there are provided devices and method useable for forming opening in the trabecular meshwork of eyes to facilitate drainage of aqueous humor and resultant lowering of intraocular pressure.

In accordance with one aspect of the present invention, there is provided a device which comprises a shaft and a distal member or foot on a distal end of the shaft. The distal member or foot may have a forward tip, a right edge, a left edge and a transversely concave depression, cavity or space between the right and left edges. The distal member is insertable into Schlemm's canal of an eye and thereafter advanceable through Schlemm's canal such that trabecular meshwork tissue will be cut by the right and left edges. In some embodiments, the edges may incline. In some embodiments, the edges may be non-parallel and may twist, rotate, curl or otherwise change in orientation as they progress rearwardly. In some embodiments, the device may optionally include lumens, opening or ports and associated connectors for infusing irrigation fluid and/or aspirating fluid and/or matter from the eye. In some embodiments, the width of the distal member and/or the width between the edges may become wider as it progresses rearwardly

Further in accordance with the invention, the distal member may comprise a forward tip, right and left edges and wing members. The right and left edges extend over leading surfaces of the wing members.

Further in accordance with the invention, there are provided methods for using the devices of the present invention to form openings in trabecular meshwork tissue of mammalian eyes, as described herein.

Still further aspects and details of the present invention will be understood upon reading of the detailed description and examples set forth herebelow.

BRIEF DESCRIPTION OF THE DRAWINGS

4) The following detailed description and examples are provided for the purpose of non-exhaustively describing some, but not necessarily all, examples or embodiments of the invention, and shall not limit the scope of the invention in any way.

FIG. 1 shows one embodiment of a surgical hand piece device of the present invention.

FIG. 2 is an enlarged view of a distal portion of the device of FIG. 1.

FIG. 3 is a side view of a distal portion of the device of FIG. 1.

FIG. 3A shows a work piece cut to form the distal member of the device of FIG. 1.

FIG. 4 is a front view of a distal portion of the device of FIG. 1.

FIG. 4A is an enlarged view of portion 4A of FIG. 4.

FIG. 4B is a side view of FIG. 4 labeled to indicate a blade axis (BAX) over which TM tissue advances in accordance with one method of the present invention.

FIG. 5 shows a distal portion of the device of FIG. 1 modified to include optional serrated regions.

FIG. 5A is an enlarged, schematic diagram of edges of the device of FIG. 5 with plane of orientation indications shown at three locations along the left edge.

FIG. 6 is a side view of the distal portion of shown in FIG. 5.

FIG. 6A is a transverse cross sectional view through Line 6A-6A of FIG. 6.

FIG. 6B is a transverse cross sectional view through Line 6B-6B of FIG. 6.

FIG. 6C is a transverse cross sectional view through Line 6C-6C of FIG. 6.

FIG. 6D is a transverse cross sectional view through Line 6D-6D of FIG. 6.

FIG. 7 is a diagram showing the device of FIGS. 5-6 being used to form an opening in TM tissue in a human eye in accordance with a method of the present invention.

FIG. 8 shows a distal portion of another embodiment of a surgical hand piece device of the present invention.

FIG. 8A is a partial enlarged view of the device of FIG. 8.

FIG. 8B is a partial left side view of the device of FIG. 8.

FIG. 9 shows a workpiece cut from tubular stock useable to form a distal portion of the device of FIG. 8.

FIG. 10 shows a distal portion of the device of FIG. 8 modified to include optional serrated regions.

FIG. 11 is another diagram showing the device of FIGS. 5-6 being used to form an opening in TM tissue in a human eye in accordance with a method of the present invention.

DETAILED DESCRIPTION

The following detailed description and the accompanying drawings to which it refers are intended to describe some, but not necessarily all, examples or embodiments of the invention. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The contents of this detailed description and the accompanying drawings do not limit the scope of the invention in any way.

Described below and shown in the accompanying drawings are non-limiting examples of devices for manually cutting a strip of TM while avoiding damage to the back wall of Schlemm's canal. In these examples, the devices may be sized for ab interno access through a small incision into the anterior chamber of the eye (typically a small corneal incision). Furthermore, the working end or distal tip of each device may be sized relative to the anatomy of Schlemm's canal and properly oriented with respect to the shaft that transverses between the incision point and the treatment zone of Schlemm's Canal in order to be functional to remove a strip of TM tissue via an ab interno approach.

Removing a strip of TM tissue is critical to expose collector channels in the distal wall of Schlemm's canal to allow outflow of aqueous from the eye and lower intraocular pressure in glaucoma patients.

FIGS. 1 through 4B show one possible embodiment of a surgical handpiece device 10 according to the present invention. This handpiece 10 generally comprises a handle 30, a shaft 12 that extends distally from the handle 30 and a distal member 14 (which is alternatively referred to herein as a “foot”) on the distal end of the shaft 12. In this example the distal member 14 has a bottom surface B, right and left upwardly extending side walls 22 and a cavity or open area 18 between the side walls 22 and rearward of the forward tip 16. The forward tip 16 may be tapered to a blunt point as shown. As explained in greater detail below, edges 20 form the sides of the forward tip 16 and transition in orientation as they progress in the rearward direction to form spaced-apart, upwardly-sloping top surfaces of the sidewalls 22. All or portions of the upwardly sloping regions of edges 20 may be sharpened, beveled, serrated, or otherwise configured to form cutting regions 21 which facilitate cutting of tissue as it advances over those edges 20. Also, the side walls 22 and/or edges 20 may be non-parallel such that the space 18 between the sidewalls 22 and/or edges 20 becomes wider as it progresses in the rearward direction. This optional widening or non-parallelism of the side walls 22 and/or edges 20 may serve to transverse stretch or transversely tighten tissue as it advances up the progressively-widening, upwardly-sloping regions of edges 20.

Optionally, the device 10 may include lumens, outlets and connectors for infusion of irrigation fluid into and/or aspiration of fluid/matter. In the example shown in FIGS. 1-4B, the shaft 12 comprises an inner tube 24 and an outer tube 26. The inner tube 24 extends out of and beyond the distal end of the outer tube 26, as shown. The inner tube 24 has a smaller outer diameter than an inner diameter of the outer tube 26 such that when inner tube 24 is positioned within the outer tube 26, for example, substantially coaxial therewith, the outer tube 14 inner surface is spaced apart from the inner tube 24 outer surface thereby defining an annular lumen which communicates with outlet port 28. The distal end of the outer tube 26 tapers down and is in sealing contact with the outer surface of the protruding inner tube 24, as shown. The opening 28 is positioned slightly above the location where the inner tube 24 exits the distal end of the outer tube 26.

The inner tube 24 has an open distal end which is positioned immediately above the space 18 defined between the edges 20 and side walls 22. As seen in FIG. 2, embodiments which include the optional infusion and/or aspiration may also have tubular infusion and aspiration connectors 32, 34 for connecting sources of irrigation fluid and aspiration to the desired irrigation/aspiration lumens of the shaft 12.

More specifically, in the particular non-limiting example shown, tubular connector 32 is configured for connection to a source of irrigation fluid and communicates with the annular lumen that extends through the outer tube around the outer surface of the inner tube 24, thereby facilitating infusion of irrigation fluid through the outer tube 26 and out of opening 28. Tubular connector 34 is configured for connection to an aspiration pump or suction source to facilitate aspiration of fluid and or other matter from the space 18, into the open distal end of inner tube 24, through the lumen of inner tube 24 and out of tubular connector 34.

In many procedures it will be beneficial to have active irrigation (to pressurize and maintain the volume of the anterior chamber and to open access between the top of iris and the inner surface of the cornea to facilitate access to the TM) and active aspiration (to clear visualization of the treatment area from debris and blood reflux) during angle surgery procedures. Active irrigation also generally eliminates the need to inject viscoelastics into the angle during surgery, saving surgical costs as well as improving the surgical view of the TM (use of viscoelastics often distorts the view of the TM due to changes in refractive index between the viscoelastics and the irrigation fluid) However, if the device 10 includes the optional infusion/aspiration capability as described herein and the user does not wish to use irrigation or aspiration in a particular procedure, the user may optionally purge the air from the I/A channels and connect the irrigation and aspiration connectors 32, 34 together. Alternatively, in some embodiments, the I/A channels may be plugged or non-existent. In procedures where irrigation and aspiration are not used or unavailable, viscoelastic may be injected into the anterior chamber of the eye to maintain access to and visualization of the angle during the procedure.

In embodiments that are equipped with the optional irrigation/aspiration capability, aspiration flow rates of approximately 10-12 ml/min may be desirable to keep the field clear of reflux blood, stabilize TM during excision, and effect removal by aspiration of the cut strip of TM tissue without requiring use of an additional instrument (e.g., forceps) for the removal. Aspiration flow rates in the greater range of approximately 4-15 ml/min may also have some utility, and all aspiration flow rates >0 ml/min may be effective to at least clear reflux blood accumulation.

The bottom B of the distal member 14 is preferably smooth and atraumatic to the outer wall of Schlemm's Canal or to the collector channels that emanate from Schlemm's Canal when the distal member 14 is inserted in and advanced through Schlemm's Canal in the manner described herein. The distal member 14 in this non-limiting example is transversely concave or U-shaped, as may be appreciated from the FIG. 6, including the transverse cross sectional views of FIGS. 6A through 6D. However, it is to be understood that the distal member 14 may have other alternative shapes including trough-like shapes, V-shapes, or other shapes in which a transverse cavity or depression exists between edges 20. The bottom surface B of the distal member 14 is preferably smooth and/or otherwise configured such that it will not cause trauma or clinically significant damage to the outer wall of Schlemm's Canal as the distal member 14 is advanced through Schlemm's Canal as described herein. The forward tip 16 of the distal member 14 may be pointed or otherwise configured to easily pierce through the TM for entry of the tip and distal member into Schlemm's Canal. However, this tip 16 (including its edges) is preferably sufficiently blunt and/or atraumatic so as not to damage the distal wall of Schlemm's Canal or collector channels which emanate from Schlemm's Canal as the distal member 14 is advanced, tip 16 first, through the TM and into and while advanced along Schlemm's Canal. The tip 16 may also help to guide the distal member along the path of the lumen of Schlemm's Canal as the distal member is advanced through Schlemm's Canal.

In the non-limiting example shown, the upper surface of the distal member is generally trough-shaped (e.g., U-shaped), with the first and second inclined side walls 22 onto which are formed tissue-severing edges or blades 20. These edges 20 are spaced apart, as shown.

The open distal end of the inner tube 24 is positioned at the top of the cavity 18 that exists between the side walls 22 of the distal member 14 such that aspirated matter or a strip of tissue severed by the edges 20 travel through the elongate cavity 18 and into the open distal end of inner tube 24. Also, when both aspiration and irrigation are employed, such capabilities of the device 10 may enable the operator to maintain a stable, desired fluid pressure within the anterior chamber of the eye. In addition, flow from the irrigation to the aspiration port of the device serves to maintain visualization of the treatment area by actively removing any tissue debris and/or blood reflux typically associated with collector channel exposure to the anterior chamber during such angle procedures.

When provided as a sterile disposable, the general surgical steps for use of the embodiment shown in FIG. 1 above, either with or without active I/A during the surgical procedure, are described in detail as follows:

First Option: Use with Ophthalmic I/A System: 1. Inspect all packages prior to use. Do not use if package is open or damaged. 2. Remove the Handpiece from its package in the sterile field. 3. Connect the irrigation connector 32 of the Handpiece to the irrigation line connector of the I/A system's fluidics set. Connect the aspiration connector of the Handpiece 34 to the aspiration line connector of the I/A system's fluidics set. Place the Handpiece inclined tip down (with the purge chamber in place). 4. Activate I/A system's irrigation and aspiration, and purge the fluid lines until all bubbles are removed in both the Handpiece and I/A system's irrigation and aspiration lines. Turn off thel/A system's irrigation and aspiration. 5. Perform a clear corneal incision using surgical knife. Allowing the anterior chamber to de-pressurize facilitates blood congesting into Schlemm's canal, helping identify the location of the TM. 6. Carefully remove the purge chamber/clear cap 36 from the device 10 so the shaft 14 member does not touch the purge chamber. 7. The raised indicators 30 on the handpiece device 10 correspond to, and are a guide to, the rotational orientation of the distal member 14 and should be held perpendicular to the corneal incision. 8. Activate irrigation of thel/A system. Insert the shaft 12 of the handpiece device 10 through the corneal incision and into the anterior chamber of the patient's eye. The anterior chamber should deepen when the irrigation opening 28 of the handpiece device 10 clears the corneal incision and irrigation fluid begins to flow into the anterior chamber. 9. Advance the distal member 14 toward the TM opposite of the incision site. Establish gonioscopic view of the TM and proceed with advancing the member until it's smooth bottom surface B contacts the TM. 10. Pierce the TM with the pointed forward tip 16 so the distal member 14 enters Schlemm's Canal while avoiding damage to the back wall. 11. Activate aspiration of the I/A system (keeping irrigation also activated). The distal member 14 is then advanced along Schlemm's Canal in the direction intended to sever TM. Examples of this are shown in FIGS. 7 and 11 and are discussed more fully below. The smooth bottom surface B of the distal member 14 should exert only minimal pressure against the back wall of Schlemm's canal as the distal member 14 is advanced in the forward direction through Schlemm's canal. 12. As TM is excised, blood reflux or hyphema from collector channels may appear. The irrigation/aspiration components of the device 10 may be used to flush any such blood or other debris from the anterior chamber thereby improving or maintaining clear visualization of the treatment area. 13. Once a strip of TM tissue has been severed and detached, if it is not fully removed by aspiration through the inner tube 24 as described above, micro-forceps can be used to manually grasp and remove such tissue in accordance with operative techniques known in the field of Ophthalmology. 14. Gently remove the shaft 12 and distal member 14 from the corneal incision following the same orientation procedure using the raised indicators 30 as used during insertion. 15. At the end of the procedure, it is recommended to thoroughly remove any viscoelastic that may have been used, using standard I/A practice to avoid post-operative pressure spikes. Second Option: Use without Ophthalmic I/A System: 1. Inspect all packages prior to use. Do not use if package is open or damaged. 2. Remove the handpiece device 10 from its package in the sterile field. 3. It is important to remove air from the Handpiece and its I/A pathways to avoid air bubbles entering the anterior chamber. Connect the irrigation tubing connector 32 to a syringe containing BSS. In some embodiments, the irrigation connector 32 and/or aspiration connector 34 may be marked or color coded to easily distinguish one from the other. Place the handpiece device 10 with the shaft 12 inclined tip down (with the purge chamber/clear cap 36 in place) and hold purge chamber/clear cap 36 in place. Infuse BSS until the BSS exits the aspiration connector 34. Remove the syringe and connect the irrigation connector 32 and the aspiration connector 34 together. The irrigation and aspiration connectors may be configured (e.g., male Luer and female Luer) so as to directly connect to one another in this manner. 4. Perform a clear corneal incision using surgical knife. 5. Inject a viscoelastic into the anterior chamber to inflate and maintain its volume during the procedure. The volume of anterior chamber must be re-established and maintained per this step for continuing the procedure. 7. Carefully remove the purge chamber/clear cap 36 from the device 10 so the shaft 12 member does not touch the purge chamber. 8. The raised indicators 30 on the handpiece device 10 correspond to, and are a guide to, the rotational orientation of the distal member 14 and should be held perpendicular to the corneal incision. 9. Insert the shaft 12 and distal member 14 through the corneal incision and into the anterior chamber of the patient's eye. 10. Advance the distal member 14 toward the TM opposite of the incision site. Establish gonioscopic view of the TM and proceed with advancing the member until it's smooth bottom surface B contacts the TM. 11. Pierce the TM with the pointed forward tip 16 so the distal member 14 enters Schlemm's Canal while avoiding damage to the back wall. 12. The distal member 14 is then advanced along Schlemm's Canal in the direction intended to sever TM. Examples of this are shown in FIGS. 7 and 11 and are discussed more fully below. The smooth bottom surface B of the distal member 14 should exert only minimal pressure against the back wall of Schlemm's canal as the distal member 14 is advanced in the forward direction through Schlemm's canal. 13. As TM is excised, blood reflux or hyphema from collector channels may appear. Viscoelastic and/or BSS may be used to improve visualization in accordance with operative techniques known in the field of Ophthalmology. 14. Once a strip of TM tissue has been severed and detached, micro-forceps can be used to manually grasp and remove such tissue in accordance with operative techniques known in the field of Ophthalmology. 14. Gently remove the shaft 12 and distal member 14 from the corneal incision following the same orientation procedure using the raised indicators 30 as used during insertion. 15. At the end of the procedure, it is recommended to thoroughly remove any viscoelastic that may have been used, using standard I/A practice to avoid post-operative pressure spikes. When performing the surgical procedure without active irrigation and aspiration, it can be appreciated that the device 10 depicted in FIG. 1 could alternatively be provided without irrigation connector 32 and associated tubing to the handpiece, as well as being provided without aspiration connector 34 and associated tubing to the handpiece. In addition, device 10 could also alternatively be provided such that the outer irrigation tube 26 does not have an irrigation opening 28. For this alternative of device 10, the surgical procedure described under SECOND OPTION above can be performed without performing Step 3, thus facilitating ease of use and reducing surgical time.

For insertion of the device 10 the incision into the anterior chamber may be approximately 180 degrees (e.g., about diametrically opposite) from the sector of Schlemm's canal from which the operator intends to cut TM tissue. Such location of the incision allows for the shaft 12 and distal member 14 to be advanced centrally across the anterior chamber of the eye to the treatment sector of the angle that is about 180 opposite the incision (for example, if the incision is temporal, the treatment sector is nasal—the most commonly employed surgical approach).

Using this approach, it is important that the forward tip 16 of the distal member 14 be in the proper orientation relative to the shaft 12 to allow for piercing of the TM by the forward tip 16 as well as facilitating the ability to advance the distal member 14 of the device 10 into and along Schlemm's canal. In addition, this arrangement can provide for removal of TM from the desired treatment sector by advancing the distal member 14 through Schlemm's canal first in one direction (e.g., clockwise) and then in the other direction (e.g., counter-clockwise).

As labeled in FIG. 3, a longitudinal axis LAX is projectable through the shaft 12. A linear transverse axis TAX is projectable tangentially to the bottom surface B at the forward tip 16, as shown. The angle A1 between longitudinal axis LAX and transverse axis TAX may be about 85 degrees for optimal surgical utility. This allows one single device to perform both clockwise and counter-clockwise TM removal relative to the incision entry point into the anterior chamber. If angle A1 ranges between about 70 to 100 degrees good clinical utility will typically result in most eyes. However, so long as angle A1 is from about 30 degrees to about 120 degrees, some clinical utility would be maintained.

If there is curvature to or compound angling of the shaft 12 or any portion of the device 10 that inserts into the eye, then the angle perpendicular to the incision site relative to the angle of the distal member 14 at the treatment site may desirably be approximately 90 degrees (despite intervening angling or curvature), with clinical utility if this angle ranges from about 30 degrees to about 120 degrees.

With respect to proper sizing, it is desirable for the shaft 12 and distal member 14 to be insertable through a minimal incision size. It can be appreciated that the current invention can be designed without irrigation and aspiration, potentially using a solid probe shaft and/or by other means. However, with inclusion of I/A capability, this may limit insertion size through about a 1.8 mm incision for sufficient inflow and outflow. However, the device would still have clinical utility if insertable through an incision of less than 2.8 mm (since such incision sizes are commonly used for cataract removal surgery).

Also with respect to proper sizing, it can be appreciated that the device will be guided down Schlemm's canal when severing a strip of TM. In its natural state, the basic lumen width of Schlemm's Canal is approximately 350 microns, or about 0.014 inches. In addition, the canal lumen is noncircular and basically collapsed in height (often described as about approximately 25-50 microns, or 0.001-0.002 inches).

For proper sizing of the member features of the device, it can be appreciated that the TM forming the front wall of Schlemm's Canal demonstrates a high degree of elasticity, and the scleral back wall of Schlemm's canal is much less elastic but deformable. These factors need to be considered for sizing features of the tip of the device since the pointed tip will be used to gain entry into and help guide the member down the lumen of Schlemm's canal as it is advanced.

An important sizing factor is the general width of the member in the direction it is advanced along Schlemm's canal. Although the TM is elastic, the tip of the member must be insertable into the lumen of Schlemm's canal and must be advanceable, together with the portion of the member that lies between the tip and the point at which the tissue-severing blades on the inclined side edges cause the TM to sever as it is advanced.

FIG. 4 shows front and side views of the tip of the device

With reference to the showing of FIGS. 4, 4A and 4B, the forward-most portion of the distal member 14 may have a first width W1. Width W1 may be about 230 microns (0.009 inches). For good clinical utility, given the elasticity and deformity of Schlemm's canal, this width W1 may vary between about 150-300 microns (0.006-0.012 inches), and some clinical utility is likely maintained between 50-500 microns (0.002-0.020 inches).

When the forward tip 16 pierces the TM and the distal member 14 is advanced into Schlemm's Canal, the back wall of Schlemm's canal will be juxtaposed to the bottom surface B. As the distal member 14 advances through Schlemm's canal, the TM tissue will ride over and advance up the inclined portions of edges 20 and edges 20 will thereby cut a strip of TM tissue.

With specific reference to FIG. 4B, as the distal member 14 advances through Schlemm's canal, TM tissue will ride over the edges 20 generally along axis BAX as the edges incline. The angle A2 shown between transverse axis TAX and axis BAX depends on the angle of incline of each edge 20. The right edge 20R and left edge 20L may incline at the same or different angles A2. In the particular non-limiting example shown, both edges 20 incline at the same angle A2, which is preferably about 35 to 40 degrees as shown in FIG. 3, as this will place the TM under tension over a reasonably short distance along path 20 of the member so that the length of the member can remain compact. However, it is reasonable to assume that angle A2 could provide good clinical utility over the range of about 30 to 50 degrees, and maintain some clinical utility over a range between about 20 to 70 degrees.

As TM tissue advances over the edges 20, the incline of the edges will cause the TM tissue to be lifted away from the back wall of Schlemm's canal. At the same time, in embodiments where the width between the edges (e.g., W1, W2, W3) becomes wider, such widening may also transversely pull or stretch the TM tissue as it advanced over edges 20. This separation between the TM and the back wall of Schlemm's Canal, as well as transverse widening between edges in embodiments where the width between the edges becomes wider, stretches the TM as it advances over the top surface of the tip and up the inclined tissue-severing blades 20, causing the TM to be opened by the two tissue-severing blades 20, thus creating a strip of TM. In embodiments where the tissue-severing blades 20 are generally separated by a distance W2, the strip of TM being severed by the blades will be roughly the width of W2, the distance between the tissue-severing blades 20. However, the actual width of the excised TM strip will vary from W2 due to the effects of the TM being stretched during excision. As shown in FIGS. 5 through 6D, some embodiments of the device 10 may have a distal member 14 a whereon the edges 20 have regions 21 which are sharpened, beveled, serrated, stepped, roughened, or otherwise configured to enhance or facilitate cutting of the TM tissue. In the non-limiting example shown, these regions 21R, 21L are of serrated configuration and are formed on the inclined portions of both edges 20R and 20L. It is to be appreciated that in some embodiments and/or for some applications such region(s) 21 may be present on only one of the edges 20R or 20 L and/or regions 21 of differing configuration may be present on the opposite edges.

Also, as may be appreciated particularly from the showings of FIGS. 5A and 6A through 6D, in the example shown, the edges 20R, 20L may be non-planar and may rotate or curl as they progress in the rearward direction. FIG. 5A shows only the edges 20 of the device of FIG. 5, without the adjacent structures. FIGS. 6A through 6D show transverse cross-sectional views through spaced-apart locations A-A, B-B, C-C and D-D of FIG. 6. From these views, one can readily appreciate that, in this example, the edges are non-parallel and actually rotate or curl as they progress in the rearward direction. At a location near the forward tip 16 the edges may be vertical or nearly vertical and converge at the forward end to form a pointed or blunt point on the forward tip 16 that is capable of penetrating through TM tissue, as explained above. As labeled on FIG. 5A, an angle A3 is defined between each edge 20 and a horizontal transverse plane. As the edges 20 progress rearward, they progressively increase in height and rotate inwardly, as shown the cross-sectional views of FIGS. 6B and 6C. As labeled on FIG. 5A, at a location reward of angle A3 (e.g., at a point where the edges 20 begin to incline) the edges 20 are at an angle A4 relative to horizontal, such angle A4 being greater than angle A3. As the edges progress further rearward, they further rotate or curl to attitudes in past horizontal as seen in the cross-section of FIG. 6D As labeled on FIG. 5A, at a location reward of angle A4 (e.g., at a point about midway up the inclined portions of edges 20) are disposed at an angle A5 relative to horizontal, such angle A5 being greater than angle A4 and, in this example, greater than 180 degrees.

The entire foot or distal member 14 may be formed of metal or other suitable material of a constant thickness. In particular, the thickness of the wall that forms the bottom B of the distal member 14 may remain constant, non-increasing and devoid of any upward sloped or planar ramp in the region that extends rearward from the front or distal tip 16 to the back or proximal side of the foot or distal member 14. In use, as shown in FIG. 7, as the distal member 14 advances through Schlemm's canal, TM tissue will ride over the non-planar, progressively rotating edges 20 and will bridge or be suspended across the open cavity 18 until the edges 20 (with or without optional cutting surfaces 21) have formed cuts or severances in the TM tissue. The resultant strip of laterally cut or severed TM tissue may then be aspirated from cavity 18 into the open distal end of tube 24, in embodiments which utilize aspiration.

The described member of the device can be fabricated by cutting a tube with the proper pattern that allows for subsequent formation of the tip features.

As illustrated in FIG. 3A, the distal member 14 of the device 10 may be manufactured by cutting (e.g., laser cutting) and then bending a distal portion of tube 24 such that the desired features of the distal member 14 are formed. As part of this cutting of the tube 24, the tissue-severing edges 20 with or without cutting surfaces 21 can be formed concurrently with the cutting or by secondary processing relative to cutting of the tube (either before or after forming of the member from the cut tubing).

When the tip is formed, the support members 25 may be formed and interconnected as seen in FIG. 3 to reinforce the strength of the distal member 14 in its formed configuration. It can be appreciated that there are many alternate cut patterns for the tube, inclusive or exclusive of features such as the support members, or any particular configurations thereof, that can be used to cut and form the member features of the current device.

The invention described to this point indicates an example of a preferred configuration and its sizing and orientation preferences and ranges. There are additional variations offering functional utility that are part of this disclosure.

FIGS. 8 through 11 show another embodiment of the device 10 b. In this embodiment, the device 10 b may be of the same construction as described above with respect to the first embodiment 10A, except that this device 10 b has a different distal member 14 b. In this device 10 b, the distal member 14 b has a bottom B, forward tip 58, edges 56 and winged members 62 with open areas 64 located rearward of the wing members 62.

Optionally, this device 10 b (or any other device of this invention including the first embodiment 10) may include a pointer 50 positioned above the wing member 62. The pointer 50 may have a tip 52 which is directly aligned with the forward tip 58. As may be appreciated from FIG. 11, during use, the pointer 60 remains above the TM tissue so as to be readily visible to the operating surgeon even though the forward tip 58 and parts of the wing members 62 may be obscured because they are beneath the TM tissue. The surgeon may then use the pointed 50 to confirm the exact direction in which the forward tip 58 is advancing through Schlemm's canal.

The edges 56 form inclined tissue cutting surfaces on the fronts of the wing members 62. Optionally, as seen in FIG. 10, a modified distal member 14 c may include areas or regions of edges 56 which are sharpened, beveled, serrated, or otherwise configured to form cutting regions 62 (alt) which facilitate cutting of tissue as it advances thereover.

It can be appreciated that such a tip configuration can be formed from a tubular structure using a cutting pattern as shown in FIG. 9. As illustrated in FIG. 9, a distal portion of the tube 24 is cut such that the features of the distal member 14 b can be formed. As part of this cutting of the tube 24, optional tissue cutting regions or surfaces 62 (alt) may be formed on the wing members 62 as shown in FIG. 10, and/or such tissue-severing blades may be formed by secondary processing relative to cutting of the tube (either before or after forming of the tip from the cut tubing).

Depicted in FIG. 11 is an illustration of the device having a distal member 14 b with winged members 62 and pointer 50 being advanced through Schlemm's canal. As illustrated in FIG. 11, the optional pointer 50 provides a visual indicator of the direction of the underlying tip as it is advanced along Schlemm's Canal. Arrows in FIG. 11 show superimposed irrigation and aspiration flows. The manner in which the optional pointer 50 is constructed in this non-limiting example is merely one example of the ways in which the optional pointer may be constructed and it is intended to include all alternative constructions of pointers or direction indicators in this disclosure.

In an ab interno procedure to form an opening in the TM of an eye, the forward tip 58 may be inserted through the TM and into Schlemm's Canal beneath the TM with the pointer 50 remaining above the TM. The foot or distal member 14 b or 14 c is then advanced through Schlemm's Canal with the TM tissue being severed by edges 56R and 56L on the forward aspects of wing members 62.

It is to be appreciated that, although the invention has been described hereabove with reference to certain examples or embodiments of the invention, various additions, deletions, alterations and modifications may be made to those described examples and embodiments without departing from the intended spirit and scope of the invention. For example, any elements, steps, members, components, compositions, reactants, parts or portions of one embodiment or example may be incorporated into or used with another embodiment or example, unless otherwise specified or unless doing so would render that embodiment or example unsuitable for its intended use. Also, where the steps of a method or process have been described or listed in a particular order, the order of such steps may be changed unless otherwise specified or unless doing so would render the method or process unsuitable for its intended purpose. Additionally, the elements, steps, members, components, compositions, reactants, parts or portions of any invention or example described herein may optionally exist or be utilized in the absence or substantial absence of any other element, step, member, component, composition, reactant, part or portion unless otherwise noted. All reasonable additions, deletions, modifications and alterations au to be considered equivalents of the described examples and embodiments and are to be included within the scope of the following claims. 

1. A device comprising: a shaft; a distal member positioned at a distal end of the shaft, said distal member having a forward end and a rearward end; a forward tip formed at the forward end of the distal member; a right edge and a left edge progressing rearwardly from the forward tip; a depression, trough, cavity or open area rearward of the forward tip and between the right edge and the left edge; wherein at least portions of the right and left side edges are configured to cut tissue as the tissue advances in the rearward direction over the right and left edges.
 2. A device according to claim 1 wherein at least portions of the right and left edges are serrated.
 3. A device according to claim 1 wherein the right edge and left edge revolve as they progress rearward.
 4. A device according to claim 1 wherein the right edge and left edge increase in height as they progress rearward.
 5. A device according to claim 1 wherein the right edge and left edge increase in height and rotate as they progress rearward.
 6. A device according to claim 3 wherein, at a first location on the front tip, the right edge and left edge are positioned at a first height and oriented at a first orientation that is vertical or near vertical.
 7. A device according to claim 6 wherein, at a second location rearward of the first location, the right edge and left edge are higher than at the first location and have each rotated to a second orientation between horizontal and vertical and further from vertical than the first and orientation.
 8. A device according to claim 7 wherein, at a third location rearward of the second location, the right edge and left edge are higher than at the second location and have each further rotated to a third orientation that is past horizontal and sloping downward toward the cavity.
 9. A device according to claim 8 wherein, at a fourth location rearward of the third location, the right edge and left edge are higher than at the third location.
 10. A device according to claim 8 wherein, in a region that includes the third location, the right and left edges are configured to cut tissue.
 11. A device according to claim 10 wherein, within said region, the right and left edges have serrations.
 12. A device according to claim 1 further comprising an aspiration lumen.
 13. A device according to any of claims claim 1 through 11 further comprising an irrigation lumen
 14. A device according to any of claims claim 1 through 11 further comprising an aspiration lumen and an irrigation lumen.
 15. A system comprising a device according to claim 12 in combination with an aspiration pump connected to the aspiration lumen.
 16. A system according to claim 15 wherein the aspiration pump is part of a phacoemulsification console or phacoemulsification surgical system.
 17. A method for using a device according to claim 1 to form an opening in trabecular meshwork tissue of an eye having a Schlemm's Canal, an anterior chamber and a trabecular meshwork, said method comprising the steps of: inserting into the anterior chamber a distal portion of said device, said distal portion including the distal member; advancing the distal member, front tip first, through the trabecular meshwork and into Schlemm's Canal; and advancing the distal member, front tip first, through Schlemm's Canal such that trabecular meshwork tissue contacts and is severed by the right and left edges of the distal member.
 18. A method according to claim 17 wherein the device further comprises an aspiration lumen and wherein the method further comprises aspirating tissue and/or fluid through the aspiration lumen.
 19. A method according to claim 18 wherein the device further comprises an irrigation lumen and wherein the method further comprises delivering fluid into the eye through the irrigation lumen.
 20. A method according to claim 19 wherein hyphema or collection of blood within the anterior chamber occurs and wherein irrigation and aspiration are used to clear blood from the anterior chamber.
 21. A method according to claim 18 wherein trabecular meshwork tissue that is severed during the procedure is aspirated into the aspiration lumen. 22.-36. (canceled) 